readCsv
The read_csv
method will read a CSV file into an in-memory table.
Syntax
import io.deephaven.csv.CsvTools
readCsv(path)
readCsv(path, csvSpecs)
Parameters
Parameter | Type | Description |
---|---|---|
path | String | The file to load into a table. |
header optional | Dict | Define a dictionary for the header and the data type: |
headless optional | boolean |
|
delimiter optional | char | The delimiter for the file.
|
quote optional | char | The char surrounding a string value. Default is |
ignore_surrounding_spaces optional | boolean | Trim leading and trailing blanks from non-quoted values. Default is |
trim optional | boolean | Trim leading and trailing blanks from inside quoted values. Default is |
charset optional | String | The character set. Default is |
csvSpecs optional | CsvSpecs | Specifications for how to load the CSV file. |
note
Only one format parameter can be used at a time.
Returns
A new in-memory table from a CSV file.
Examples
note
In this guide, we read data from locations relative to the base of the Docker container. See Docker data volumes to learn more about the relation between locations in the container and the local file system.
In the following example, write_csv
writes the source table to /data/file.csv
, and read_csv
loads the file into a Deephaven table.
import static io.deephaven.csv.CsvTools.readCsv
import static io.deephaven.csv.CsvTools.writeCsv
source = newTable(
stringCol("X", "A", "B", null, "C", "B", "A", "B", "B", "C"),
intCol("Y",2, 4, 2, 1, 2, 3, 4, NULL_INT, 3),
intCol("Z", 55, 76, 20, NULL_INT, 230, 50, 73, 137, 214),
)
writeCsv(source, "/data/file.csv")
result = readCsv("/data/file.csv")
- source
- result
note
In the following examples, the example data found in Deephaven's example repository will be used. Follow the instructions in the README to download the data to the proper location for use with Deephaven.
In the following example, read_csv
is used to load the file DeNiro CSV into a Deephaven table.
import static io.deephaven.csv.CsvTools.readCsv
result = readCsv("https://media.githubusercontent.com/media/deephaven/examples/main/DeNiro/csv/deniro.csv")
- result
In the following example, read_csv
is used to load the file DeNiro TSV into a Deephaven table. The second argument, "\t"
, indicates that the file contains tab-separated values.
import static io.deephaven.csv.CsvTools.readCsv
import io.deephaven.csv.CsvSpecs
specs = CsvSpecs.tsv()
deniroTSV = readCsv("https://raw.githubusercontent.com/deephaven/examples/main/DeNiro/csv/deniro.tsv", specs)
- deniroTSV
Any character can be used as a delimiter. The pipe character (|
) is common. In the following example, the second input parameter is used to read a pipe-delimited file into memory.
import static io.deephaven.csv.CsvTools.readCsv
import io.deephaven.csv.CsvSpecs
specs = CsvSpecs.builder().delimiter('|' as char).build()
result = readCsv("https://raw.githubusercontent.com/deephaven/examples/main/DeNiro/csv/deniro.psv", specs)
- result